I don't personnely have experiance with Brembo's on this car but I do have the AP BBK and with the street pads (Mentex? spelling??) Anyway the street pads it comes with, on the street their great, on the track they don't fade much at all and have a very long wear life, very long.

I've tracked with racing pads also and the braking ability was awesome. The AP calipers & disc are already a track set up so with street pads, you'll have a set up that is 10 fold of what you need on the street. Also go with either the AP racing brake fluid or something like Motul 600 fluid. Super easy to bleed if you have a pressure pleader. Dealership won't normally change your brake fluid with other than BMW DOT 3/4 fluid because it'll contaminate their machine, from what they told me so I bleed my brakes myself. Plus AP BBK is a bit cheaper too.

But just know that AP discs cost about $1800 flippen bucks for a new set so very expensive, but you won't wear them down for a number of years with daily street driving. Those discs are made to take the abuse of the track with racing pads.

Also be warned, and I learned this the hard way, that with any BBK you put on, DON'T, DON'T use acid type wheel cleaners. You'll destroy the paint like I did on my AP's and had to repaint all the calipers and disc hats. Just purchase citric type wheel cleaners online such as Sonax or other products from like Chemical Guys, etc. Just stay away from the wheel cleaners with acid. Spend $6,000+ and then screw the paint up with such cleaners sucks.

This is a question I also find myself asking. Given the similar pricing, I'm strongly considering AP.

One objective factor would be the replacement cost of the rotors. Another would be the availability of pads.

Has anyone found other reasons to go for Brembo GT over AP?

BTW, a while ago, I saw some comment about an AP kit "searching for vacuum", with the symptom being that the brakes would sometimes be a bit intermittent. The post indicated that AP knew about the problem and was searching for a solution. I think it was an 8-piston caliper, but I can't find it now. Does anyone have any details on this?

I had been waiting to post more until the OP came back on, but he seems to have disappeared. So, I'm just gonna post my longer answer for others that may be interested.

Brembo and AP Racing are owned by the same parent company, although they are run as two separate entities. They're both great.

I have AP Racing. If you plan on tracking the car, the AP kit is simply awesome. Their strap drive system for the front rotors is fairly unique. (Strap Drive info: http://www.apracing.com/Info.aspx?In...7&ProductID=30 ) They never ever ever overheat assuming proper brake fluid and good pads. The brake pedal feel never changes while on track from first lap to the last. On the topic of brake fluid, don't cheap out. It's a shame to spend $6000+ on brakes, $800 on pads and then put in $25 brake fluid. Put Castrol SRF in the car and don't screw around. If you search, you can find SRF for $56/liter. (There's also a new brake fluid called Torque RT700 that is interesting and reasonably priced. I'm still learning about it: http://www.torquebrakefluid.com/)

The brake pad choice has a LOT to do with how a BBK "feels". For the track, Endless ME-20 pads are expensive ($500 for the fronts), but they have a nice feel and work very well. My staple front pad on the track has been the Mintex F3R---reasonable price (around $300, sometimes even under $200 if you can find a deal on ebay) and they work great. I get 10 track days from a set of front pads. (The rears last forever.) But I've also experimented with crazier pads like Cobalt Friction XR1.......oh my god......those pads are so high torque and powerful it's scary. You never realized a 4000lb car could slow down so fast. But they don't modulate as easily as other pads. Their job is to stop the car like it hit a wall----incredible. Plus, you really need a tire with massive grip that can handle that kind of stopping power, otherwise the ABS can activate.

And don't plan on running true track pads on the street. That experience is a misery. Track pads squeal and groan and resonate and hum and chew up the rotors when they're running cold on the street. Plus, a serious track pad is REALLY touchy on the streets----you touch the brake just a bit much and the car comes to a sudden and severe halt----not good for the dude in the car behind you----or your rear bumper. In the rear, I usually run a hybrid pad--Ferodo DS2500. I leave it in the car both street and track. But the fronts are always changed out before and after track events. You'll want to become handy at that. The AP fronts take 5 minutes per wheel to switch pads. The rear pads take just a bit longer, but it's not a big deal.

As far as replacement costs for AP rotors, they're $900/pair for the fronts. I just replaced the fronts myself. Interesting process. The strap drive really is a pretty amazing idea.

BBK's with a regular street pad don't "feel" much different on the street than the OEM brakes. That's a good thing. But they sure look cool!

I had been waiting to post more until the OP came back on, but he seems to have disappeared. So, I'm just gonna post my longer answer for others that may be interested.

Thanks, that really helps!

I assume you have the 368 mm rotor?

Have you tried Carbotech pads? That's what I finally settled on, for the Alcon brakes in my A4. I like that they're easy on the rotors, the street pads are low-dust and quiet, their street and track pads use compatible compounds, and that the dust is non-corrosive. I think they're also relatively inexpensive.

If I decide to pull the trigger on the AP kit, I'll be checking with Carbotech to see if they have a template for this caliper. If not, you can send in a used set of pads and I think they'll just reuse the backing plates.

thanks for your post OP. question, dont you need to bed in the rotors every time you swap from race to street pads?

Not if you get pads with compatible compounds. Previously, I used Carbotech ceramic pads for both track & street, and swapped without issue (Carbotech says this is okay).

Some people just drive on their track pads for a few extra days. Since track pads tend to be fairly abrasive, low speed stops will have the effect of scrubbing off the transfer layer. That cleans the rotors for use with street pads.

Another approach is to swap rotors as well as pads. Higher up-front cost & a bit more hassle, but it lets you choose track & street pads independently and without worrying about leaving the track pads in too long (which wears down the rotors) or removing them too soon (which can cause brake judder if the compounds are incompatible).

Note: The AP Racing strap drive disc assembly requires a shallower pad than the original pad to enable them to clear the strap drive system. The pad depth is 50mm as opposed to 60mm on the standard pad.

Obviously, the pad is still big enough to get the job done, but giving up 17% of your pad area seems like an unfortunate compromise. I wonder how common it really is to see debris clogging up the bobbins typically used in floating hardware, on street cars.

What they mean is when you're swapping pads and don't have a retractor tool handy, what some people do (including myself) is to unbolt the caliper, leave the old pads in, and firmly press the caliper towards or pull it away from the car (with the brake reservoir cap removed, of course). After about 30 seconds, this usually retracts the cylinders enough to accommodate a set of new pads.

With their strap drive system, this could bend the straps. Which would be bad.

But it looks like you don't normally need to remove the caliper, for pad changes? If that's true, then it would be a lot easier just to use the proper tool for the job!

Indeed, my "internet research" seems to indicate that the Brembo 07.9551.13 pad (which I think is the model for their 6-pot GT caliper) has a pad area of 189 mm (length) by 58 mm (radial) vs. the AP Racing pad's 150 mm (length) by 54 mm (radial).

If those numbers are correct (and that's a big if), it would mean the GT caliper has a pad area 35% greater. I know pad area isn't everything, but that's hard to overlook (though it basically just translates into burning through pads & rotors faster).

Can anyone with actual knowledge comment on this?

AP lists the pad area of their CP3894D54 pad as 77.44 cm^2 (source: http://109.228.5.127/ProductDetail.aspx?ProductID=3031). I can't find a comparable spec for Brembo's 07.9551.13 pad, nor actual confirmation from Brembo that this is the correct pad for the Monobloc 6-piston GT Kit# 1NX.XXXX (and I can only find a hint, in their application sheet, that this is the correct caliper for the E92).

[AP definitely wins on the amount of specs they provide. Does Brembo really have no datasheets or mechanical drawings on their website?]

Pad friction area is irrelevant. The only thing that matters is the usable volume of the friction material - pad friction area times usable depth. That matters because it determines how often you have to change pads. And, for track day use, that really doesn't matter because you're only running 1/2 hour at a time.

This is the shape for the e92 m3 N caliper (both 380 and 365). I just swapped in my set of me20 today. Thickness including backing plate is 18mm. These pads are very very large.

IMO a larger friction area should distribute more effectively, leading to lower wear rate. Stopping power is not affected.

Quote:

Originally Posted by Drifty//

Indeed, my "internet research" seems to indicate that the Brembo 07.9551.13 pad (which I think is the model for their 6-pot GT caliper) has a pad area of 189 mm (length) by 58 mm (radial) vs. the AP Racing pad's 150 mm (length) by 54 mm (radial).

If those numbers are correct (and that's a big if), it would mean the GT caliper has a pad area 35% greater. I know pad area isn't everything, but that's hard to overlook (though it basically just translates into burning through pads & rotors faster).

Can anyone with actual knowledge comment on this?

AP lists the pad area of their CP3894D54 pad as 77.44 cm^2 (source: http://109.228.5.127/ProductDetail.aspx?ProductID=3031). I can't find a comparable spec for Brembo's 07.9551.13 pad, nor actual confirmation from Brembo that this is the correct pad for the Monobloc 6-piston GT Kit# 1NX.XXXX (and I can only find a hint, in their application sheet, that this is the correct caliper for the E92).

[AP definitely wins on the amount of specs they provide. Does Brembo really have no datasheets or mechanical drawings on their website?]

The AP kit is 368mm on the front. I don't know of any other options in terms of rotor size. With the rotor, you have a choice of slotted-only, or slotted and drilled. Usually there's no cost difference between the two, but if you're going to track the car regularly, people say slotted-only is better because the rotor is stronger/better than the drilled rotor for tracking. As far as aggressive looks, many people like the drilled looked.

@Drifty//:
As far as the strap drive system, I can tell you it is not delicate or fragile. I've done almost 100 pad swaps in the last year on the fronts, and I've never had so much as a hiccup from the rotors. I know AP puts the fear of God in you with that documentation, but I've actually changed the rotor rings myself. That strap drive design is a piece of artwork.

I have never tried Carbotech pads myself. I would love to try a bunch of brands, but it's expensive, and you don't burn through them super fast, so you can end up with a set for awhile. I guess you could sell ones you don't like, but the AP kit is kind of rare, so there's not a ton of guys out there buying used pads.

I can't comment on the size of the Brembo pads, but I can assure you, stopping power with the AP kit is NOT a problem. I have funny story about having an instructor in the car with me. When he was in the car with me, I had already had the AP kit for awhile and had built up the trust in them to the point that I use the hell out of them. I late-brake fairly aggressively because I know they'll be there for me. (Whether the tires will be there is another story..... ) Plus, I have a blower, so the car's going even faster than stock would. So, we're at Willow Springs which has a fairly long front straight, and we do several laps---all in complete control, not a single out-of-control moment. Now this instructor is an INSTRUCTOR. He's not a guy looking for free track days. He instructs for teams, etc. So, he gets out of the car, and we're talking and he's giving me notes. And then he stops, looks at me and smiles and says "you know that you're using every ounce of those brakes right?" I laughed and said "yeah I know. I trust them. They have never failed me in any way, so I really work them." He smiled again and said, "yeah, well I tell ya, I've been around the block, and you gave me a couple sphincter moments there....." But he didn't tell me to back off. He was just confirming that I was getting everything you could get from brakes out there. And again, I will repeat that different pads give different stopping power, so if you want more stopping power, you can switch up to a more aggressive pad.

The pads for the AP kit have 12mm of pad material depth on them. I have found, and others seem to as well, that doing HPDE days, they are good for around 10 track days.

Couple other pieces of advice:

-There have been threads on this forum about how cleaning solutions can ruin any BBK brand's paint job. I have made the decision to NEVER use a harsh wheel cleaner. The fact is the brakes are subjected to quick and wild temperature extremes. The paint jobs have to endure this, and I think it's a tough job. Go easy on the paint jobs with cleaning chemicals. I've had mine for just over a year now, and I just use the car wash soap, and the paint has been holding up well.

-You need to come up with a reliable way to remove wheels so that when you pull them off, the barrels don't come crashing down on the calipers and scratch them. Sadly, you can't control every wheel removal and when other people take them off, they still get scratched.....ah well......

The AP kit is 368mm on the front. I don't know of any other options in terms of rotor size. With the rotor, you have a choice of slotted-only, or slotted and drilled. Usually there's no cost difference between the two, but if you're going to track the car regularly, people say slotted-only is better because the rotor is stronger/better than the drilled rotor for tracking. As far as aggressive looks, many people like the drilled looked.

@Drifty//:
As far as the strap drive system, I can tell you it is not delicate or fragile. I've done almost 100 pad swaps in the last year on the fronts, and I've never had so much as a hiccup from the rotors. I know AP puts the fear of God in you with that documentation, but I've actually changed the rotor rings myself. That strap drive design is a piece of artwork.

I have never tried Carbotech pads myself. I would love to try a bunch of brands, but it's expensive, and you don't burn through them super fast, so you can end up with a set for awhile. I guess you could sell ones you don't like, but the AP kit is kind of rare, so there's not a ton of guys out there buying used pads.

I can't comment on the size of the Brembo pads, but I can assure you, stopping power with the AP kit is NOT a problem. I have funny story about having an instructor in the car with me. When he was in the car with me, I had already had the AP kit for awhile and had built up the trust in them to the point that I use the hell out of them. I late-brake fairly aggressively because I know they'll be there for me. (Whether the tires will be there is another story..... ) Plus, I have a blower, so the car's going even faster than stock would. So, we're at Willow Springs which has a fairly long front straight, and we do several laps---all in complete control, not a single out-of-control moment. Now this instructor is an INSTRUCTOR. He's not a guy looking for free track days. He instructs for teams, etc. So, he gets out of the car, and we're talking and he's giving me notes. And then he stops, looks at me and smiles and says "you know that you're using every ounce of those brakes right?" I laughed and said "yeah I know. I trust them. They have never failed me in any way, so I really work them." He smiled again and said, "yeah, well I tell ya, I've been around the block, and you gave me a couple sphincter moments there....." But he didn't tell me to back off. He was just confirming that I was getting everything you could get from brakes out there. And again, I will repeat that different pads give different stopping power, so if you want more stopping power, you can switch up to a more aggressive pad.

The pads for the AP kit have 12mm of pad material depth on them. I have found, and others seem to as well, that doing HPDE days, they are good for around 10 track days.

Couple other pieces of advice:

-There have been threads on this forum about how cleaning solutions can ruin any BBK brand's paint job. I have made the decision to NEVER use a harsh wheel cleaner. The fact is the brakes are subjected to quick and wild temperature extremes. The paint jobs have to endure this, and I think it's a tough job. Go easy on the paint jobs with cleaning chemicals. I've had mine for just over a year now, and I just use the car wash soap, and the paint has been holding up well.

-You need to come up with a reliable way to remove wheels so that when you pull them off, the barrels don't come crashing down on the calipers and scratch them. Sadly, you can't control every wheel removal and when other people take them off, they still get scratched.....ah well......